With recent progress in computer technology, there has been a trend to produce digital electrical measuring instruments and other general industrial instruments. The world-wide development of the petroleum industry has increased the number of plants and has resulted in an increase in the required panel instrumentation in a typical central control room. This has increased the need for small-sized instruments such as vertical type recorders. The trend of miniaturizing the instrument structure has been further stimulated by the development of a novel circuit known as large scale integration.
It seems that recorders in the next generation will require both digitization and miniaturization. However, analog instruments, unlike digital equipment, are equipped with an outstanding feature that makes it possible to directly observe variations in values to be measured and the conditions of the object being controlled. Because this feature is quite useful in large-sized recorders having a large recording width, a demand for such instruments is still expected.
There is no established specific dividing line between large size and small size recorders. However, any recorder having an effective recording width greater than 150 millimeters is generally referred to as being a large size recorder.